1. Field of the Invention
This invention relates to a storage networking system, and more specifically to a file server system or a network attached storage (NAS) system configured to achieve protection of data or a file using watermarking.
2. Description of the Related Art
One of the main expectations for a storage networking system is to share data from several hosts or users on consolidated storage resources. A file server system or a Network Attached Storage system (NAS) is a typical example of a system to achieve these expectations. A file server may include elements of a typical computer such as, for example, a processor, memory, and input/output (I/O) handling capabilities. Both systems are storage networking systems to provide file IF (interface). A Content Addressable Storage (CAS) system is another example of a system to achieve these expectations. Originally, CAS products have been used to provide object IF, however, recent CAS products also provide file IF.
Recently, increasing storage security or data security has become one of the main requirements from customers. Copyright protection is one example for satisfying these requirements. In this regard, customers want to share data or files within users, but they also want to protect an owners' right from any infringement from the users. Current storage networking systems cannot solve this requirement. For example, NAS only provides file access control mechanism using ACL (access control list), which does not protect copyrights on the file.
U.S. patent application Ser. No. 20030161468 discloses a NAS system that inserts a watermark into a file when the file is stored into a NAS system. Because the inserted watermark describes copyright information in the file, the system can protect any copyright violation from users psychologically. Also, it is easy to find copyright violation, because infringing copy of the file still contains the watermark.
On the other hand, Watermark or Digital Watermark is a well known technology that enables additional information (watermark information) to be inserted or embedded into data or contents, such as image, picture, motion picture, sound, and so on. If the watermark information contains copyright information, it can protect copyright violation in terms of psychological point of view. Also, even if the copyright violation occurs, it is much easier to detect the violation, since most of the current watermark technologies enable the watermark still to exist in the violated data.
There are two types of Watermark technologies, visible watermark and invisible watermark. The visible watermark directly shows additional information such as copyright notices to users, which prevent users psychologically from violating the copyright. The invisible watermark hides the information inside data. In other words, humans cannot notify the information in the data. This is achieved by inserting the information into specific part of the data where humans visually or acoustically cannot identify.
Therefore, there is a need for copyright protection functionalities on a file server system, a NAS system, a CAS system or any other storage networking systems, without impacting any other changes to the existing IF, e.g. File IF.